The Moon Mission

[coldel]

I can understand one druken post, but to then double down on it whilst sober, then ask for it to be deleted?

[Ken_Code]

coldel said:

I can understand one druken post, but to then double down on it whilst sober, then ask for it to be deleted?

And if he was drunk enough to post what he did in the afternoon then he’s got more than one issue that he ought to work on.

[Eric Mc]

It's best NOT to delete threads like this.

Although JimH did post a rather silly premise, I would like to think that there is enough sense and genuine knowledge on here for it to be useful for those who have a true interest in spaceflight history.

[Ken_Code]

Eric Mc said:

It's best NOT to delete threads like this.

Although JimH did post a rather silly premise, I would like to think that there is enough sense and genuine knowledge on here for it to be useful for those who have a true interest in spaceflight history.

It got me interested enough again in one aspect to want to research it a bit more; how accurately did they need to measure horizontal velocity across the moon’s surface (as opposed to calculating it) and how did they do so.

[Eric Mc]

Landing radar. Basically bouncing radio waves off the lunar surface as they approached it gave them altitude and horizontal speed across the surface.

They also had a simple grid system painted etched onto the Commander's window which allowed them to judge horizontal distances and angles to known surface features ahead of the Lunar Module.

Basically, they needed to kill all horizontal movement just before touchdown as the last thing they wanted was the LM skidding across the fairly uneven terrain.

[Ken_Code]

Eric Mc said:

Landing radar. Basically bouncing radio waves off the lunar surface as they approached it gave them altitude and horizontal speed across the surface.

I’d have assumed Doppler radar, but wasn’t sure if that was the case or not.

[coldel]

Eric Mc said:

Landing radar. Basically bouncing radio waves off the lunar surface as they approached it gave them altitude and horizontal speed across the surface.

They also had a simple grid system painted etched onto the Commander's window which allowed them to judge horizontal distances and angles to known surface features ahead of the Lunar Module.

Basically, they needed to kill all horizontal movement just before touchdown as the last thing they wanted was the LM skidding across the fairly uneven terrain.

You see this is the thing...a CT will not even consider this type of information or even know about it.
They will listen only to what they want to hear, then just go with the basics of understanding of that thing and just discard anything else as noise.

Given humans worked out how to do hugely complex stuff hundreds of years ago, its not beyond the wit of mankind to work out horizontal speed above the lunar surface either. It is though beyond the wit of a CT to even try and understand it.

[Eric Mc]

Ken_Code said:

Eric Mc said:

Landing radar. Basically bouncing radio waves off the lunar surface as they approached it gave them altitude and horizontal speed across the surface.

I’d have assumed Doppler radar, but wasn’t sure if that was the case or not.

I think you are right. The LM had two separate radar systems, one attached to the descent stage for landing and another mounted on the top of the ascent stage for rendezvous and docking.

[Ken_Code]

Eric Mc said:

I think you are right. The LM had two separate radar systems, one attached to the descent stage for landing and another mounted on the top of the ascent stage for rendezvous and docking.

From the little I’ve read it seems to be the case.

Before reading I wasn’t sure if it was calculated from the accelerometers or actually measured.

I’d thought that possibly real-time Doppler-radar calculations were beyond the computing power available, but of course the equipment may not have needed any processing power at all, it could have been “hard coded” in the design.

[Eric Mc]

The computers used in Apollo were indeed "hard wired" with very limited reprogramming capability. But they were robust, reliable and fully capable of performing the tasks they were designed to do.

Here's a picture of the two LM instrument panels (Commander left and Lunar Module Pilot LMP)



This picture shows the Commander's window pane which shows the simple grid system which could be used to estimate distance and approach angle -

[Scrump]

Jim H said:

Mods. With respect and I do apologise.

Can you please delete the thread completely.

It’s adding no value.

Shame really some great stuff by Eric.

Eric has posted a very good response to this request:

Eric Mc said:

It's best NOT to delete threads like this.

Although JimH did post a rather silly premise, I would like to think that there is enough sense and genuine knowledge on here for it to be useful for those who have a true interest in spaceflight history.

[Jim H]

Scrump / Eric totally agree

There was just a bit of nastiness last night. I’d never ever come on here for that and mostly like to keep life a bit light-hearted (if one can). It’s just ugly when it goes wrong. As is already acknowledged, it was posted in the Lounge originally

It’s a fascinating forum this, every area - so much knowledge and information out there.

It was a stupid post to start off with, but it did provoke a bit of debate.

Which we all have our own thoughts, and our own points of view..

I think that should always be the case. And respectfully.

But resorting to nastiness and challenging integrity. That’s pretty poor.

I’d never do that.

[hidetheelephants]

Ken_Code said:

Eric Mc said:

I think you are right. The LM had two separate radar systems, one attached to the descent stage for landing and another mounted on the top of the ascent stage for rendezvous and docking.

From the little I’ve read it seems to be the case.

Before reading I wasn’t sure if it was calculated from the accelerometers or actually measured.

I’d thought that possibly real-time Doppler-radar calculations were beyond the computing power available, but of course the equipment may not have needed any processing power at all, it could have been “hard coded” in the design.

It was cutting edge stuff at the time, but it was paralleled by the separate development of aircraft blind landing technology which landed its first passenger-carrying flight in the 1960s; it was expensive but it could be done with the hardware available.

[Jim H]

What I mean is: don’t delete the thread.

Eric has put a lot of time and effort into the information he has posted up, whilst being extremely respectful.

Yet I can imagine wiping his brow. Educating the many.

I’m not happy with my drunken post to start with, it’s disappointing. But - we’ve all had thoughts at the those moments.

But shaking the tree and see what falls out is always educational.

[Nova Gyna]

Jim H said:

Scrump / Eric totally agree

There was just a bit of nastiness last night. I’d never ever come on here for that and mostly like to keep life a bit light-hearted (if one can). It’s just ugly when it goes wrong. As is already acknowledged, it was posted in the Lounge originally

It’s a fascinating forum this, every area - so much knowledge and information out there.

It was a stupid post to start off with, but it did provoke a bit of debate.

Which we all have our own thoughts, and our own points of view..

I think that should always be the case. And respectfully.

But resorting to nastiness and challenging integrity. That’s pretty poor.

I’d never do that.

If you propagate unfounded conspiracy theories and inaccuracies, then double down and react defensively when your credibility is challenged, don't be surprised when your integrity is questioned - after all, you can't expect people to respect nonsense just because you insist it's true.

[Jim H]

Nova Gyna said:

Jim H said:

Scrump / Eric totally agree

There was just a bit of nastiness last night. I’d never ever come on here for that and mostly like to keep life a bit light-hearted (if one can). It’s just ugly when it goes wrong. As is already acknowledged, it was posted in the Lounge originally

It’s a fascinating forum this, every area - so much knowledge and information out there.

It was a stupid post to start off with, but it did provoke a bit of debate.

Which we all have our own thoughts, and our own points of view..

I think that should always be the case. And respectfully.

But resorting to nastiness and challenging integrity. That’s pretty poor.

I’d never do that.

If you propagate unfounded conspiracy theories and inaccuracies, then double down and react defensively when your credibility is challenged, don't be surprised when your integrity is questioned - after all, you can't expect people to respect nonsense just because you insist it's true.

Like I say. It started out in the lounge - and soon got out of hand after myself having rather too much to drink and being bored.

Don’t over analyse it. I don’t.

Back to moon landing’s

[LordLoveLength]

Ken_Code said:

From the little I’ve read it seems to be the case.

Before reading I wasn’t sure if it was calculated from the accelerometers or actually measured.

I’d thought that possibly real-time Doppler-radar calculations were beyond the computing power available, but of course the equipment may not have needed any processing power at all, it could have been “hard coded” in the design.

The radars did need processing power - the rendezvous radar being active used up valuable program time and caused the 1201 / 1202 alarms during landing on Apollo 11.
Loads on it here https://doneyles.com/LM/Tales.html

[Hereward]

Anyway, Rest in Peace Bill Anders.

Apollo 8 was always the most impressive mission for me. They didn't land on the moon but they achieved so many firsts and paved the way for the rest of the missions.

[MikeM6]

Hereward said:

Anyway, Rest in Peace Bill Anders.

Apollo 8 was always the most impressive mission for me. They didn't land on the moon but they achieved so many firsts and paved the way for the rest of the missions.

I just read about Bill, very sad.

I recently hung an Earth Rise on my study wall, having picked it up at NASA in Houston. Such an incredibly provocative image and a huge contribution to humanity.

[Hereward]

Short Apollo 8 video:
https://www.youtube.com/watch?v=Syf_uLrBAJU&t=...